Repeater.



morne# wie i Y.

CMRLES L LANNNG, 0F DRCHESTER, MASSACHUSETTS.

immensen.

Speeication of Letters Patent.

Application am December i3, isos. serial No. 291,531.

. To @ZZ /w/z om t may concern g Be it known that l, CHAnLns l). LANNIN'G, a citizenA of the United States, residing a* Dorchester, in the county of Satlollc and State of Massachusetts, have invented en Improvement in Repeaters, of which the following' description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention relates to telephone repeating. ineens, and particularly to repeaingineans employed for. reinforcing the repeated currents. I Telephone repeaters ordinarily employ a receiving magnet connected to be energized by the variable current energy of the initial or transmitting circuit,.a variable resistance niedium in operative relation tothe repeating circuit, and a magnetic.l connection between the variable `resistance and the receiving niagnet, so that the variations in the line energ` l of 4the 'transmitting circuit are magnetically transmitted to the resistance and thereby impressed upon the distant listening' circuit and usually with increased force. The vari- -able resistance employed isA usually some form of Inicrophonic contact comprising a vibratory electrode so positioned with reference to a second electrode, either with or vWithout intervening granular conducting' material, that its vibrator-y movementserves to vary more or less the conductivity the microphone. The magnetic connection ordinarily comprises an armature working in the iield of the receivingI magnet, so connected to the vibratory electrode as to canse movement thereof corresponding 'to the .netic variations of the receiving ina gnet. ln

addition there is also nsually employed some factor or element for 'positioning the vibratory electrode normally with reference to its opposing electrode or electrodes and an element or factor to restore it to or j toward its normal position when moved or' displaced therefrom by the action of the magnet,- wliich. latter vibratory controlling factor may be the same as or other than the positioning factor.. For example, the diaphragin attached tothe electrode oi a solid baci transmitter,'fnlcrnined or secured as it is 'to the Walls of the casing, may be said to .perform 4die 'double function of position ine; the .electrode and controlling'its vibravliile on the other hand, there might cvedsoine elastic or other medium or a mechanical positioning element or bot -primarily positioning the vibratory e exerting a constant restoring force or the vibratory electrode, vith addition i 'r separate means for positioning or anion the electrode with reference to tire o posi' electrode. It nas not heretofore 'be n i cult to obtain mere intensification oi posted currents, but it llas been accurately to reproduce the origiml rent undulations harmoniously and distortion, owing, in large measure, to disproportionately 4sniall ernennt ene `which the current undulation" ing end of the transznittinl as compared with the eney produces them at the transmitter. ll found that a successful repeater not only a careful and etiicient tra A tion of the line current energy into energy at the receivingiii-gilet i necessary loss, but the direct tra of the magnet undulations t the Y, electrode without unnecessary inael'iani -work and with the elimination of all or features which tend to impair and sensitive response oi the elec the magnetic variations.

One objectbf Iny invention is the vision of repeating .means having` not a high magnetic eiic-iency and a direc? ot n'lagnetic action upon the electrodes, an increased responsiveness and sensiw ness oit' the electrode to the magnetic und,

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lations by eliminating the disturbing iny luences ot' a mechanical i -eration controlli By my invention l -nov te ineens trode, which ineans is vvidiont the inne l distorting effects oi a diapnregni or oth mechanical spring, while at the saine tirne acting effectively as ae vibratory controlleror positioning device for the electrode, suoli positioning and controlling function in th preferred forni of my invention being; performed by the constantly actingT and variable force of gravity. v

My invention will be lest understood bv reference to the following description, v

' taken in connect-ion with the aceonipalvll illustra-tion of one `spe( tliereo, While its scope vi ticularly pointed ont in In the dramngs,- Y vation of a teleolione accordnn(r to one loro; f Q lsa side elevation et c embodiment il be incre nd ,f uid S, similar views of a fourth modincaate" ng to the drawings, and particularly to the embodiment of my invention shown in Figs. l and 2, the transmitting circuit a, indicated conventionally in dotted lines, is connected to the coils of the receiving magnet Z), the latter being shown as of the pern'ianently magnetized horse-shoe type, connnonly employed in commercial `telephone receivers. nets may be used,` but this simple construeA Ytion gives an effective magnetic-transforma tion oiI the 'current energy.4 The magnet is preferably so associated 'with its armature c as to pro-vide a substantially complete 2U magnetic circuit, interrupted only at the aiL ,Y between the armature and the magnet core, which 4is necessary to get suitable vibratory movement of the armature. The magnetizing coils are located preferably at the extreme end of the core, so that the armature lreceives the full effect of all the magnetic 'fluit created by the coils, which latter may be split, or otherwise suitably Wound upon their cores. The magnet core shown has the interior filling d oit babbitt, or other non-magnetic material, and the core is clamped between the non-magnetic blocks c and 7", the la ter being vertically adjustable upon the stationary upright guide rods g, by means of the delicate screw adjusting de- -vice 71... ln order to secure the maximum 'elliciencyrof the armature as a part of the metallic magnetic circuit, the same is preterably constructed. in block form, that is, with a v'ew to providing a path of suitably reluctance` to receive substanentire magnetic ihn; vtrom the mag istingnished from a diaphragmatic armature, designed primarily for ini-poses of flexibility. T he larmature ably in the forni of a small, light, ir body of' soit iron, preferably nergy transformation. The armasecru'ed vtothe stud c', but insulated nn by the collar 7c. The stud c is senin-ed to the disk Z oic conducting material, to which is at' iched the vibratory electrode i m, he latter being thereby rigidly and dito the armature. The'vie herein consists of an anrelatively fixed electrode l comprising an annular upper surface of c, cooperating sur Avibratory. electrode and being conductin plate o in the base trunient.y

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Other forms of maeto eliminate lossl through eddyv and render the same more effective' meetic The circuit connections to the vibratory and relatively lined electrodes oit the micro phone described, being well understood, arc indicated conventionally and in dotted lines only, the connection to thc vibratory elec* trode to the microphone circuit, however, being preferably by means of somo light and selijsustained conductor which will offer no substantial. resistance to the movement oi' the electrode. The armature is preferably attached to the vibratory electrode and the latter is arranged vfor Inovement Ain a substantially vertical direction andv preferably with its axis of movement coinciding with the line of magnetic pull.

lt will be seen that in the described emiliodiment of my invention the pull oi the vrmignet is opposed wholly by gravity and that the pressure between the electrodes will depend upon the Weight olf the armatureelectrode and 'the connections diminished by the upward pull ot the magnet lVhen the instrument is initially adjusted the vi bratory electrode is given the desired prcS- sure upon or position relative to the lixed electrode by a suitableadjustment or proportioning of the initial field, this acting to exercise a constant upward pull upon the armature-electrode structure. Whether permanently magnetized or not the magnet is preferably given a light initial field, this permitting a reduction ot the air gapbetween the armature and the magnet core. The current undulations passing through the receiving magnet add to or detract from this initial pull tending either to raise the vibratoryV electrode against the force of gravity or permit a- 'greater proportion of the weight of the vibratory structure to be effective in pressing against the stationary electrode. lt will be seenl that in the action of this armature, not only'are the armature and its associated electrode connecte-1l rigidly and directly to form a simple composite structure with unity of .movement and action, but that the positioning and control oi the ,electrode against the .action of the 'magnet is effected by the constantly4 acting and unchanging force of gravity leaving the structure unatta'ehed to any .controlling or` positioning agents' and free to give unrestricted response to the varying pull of the magnet. This eliminates the distorting ell'ect of an electric medium, like a mechanical spring or diaphragm or of any stationarily attached positioning member, which effect is present, to a greater or less extent where such a device is employed as the principal, or primary positioning or controlling agent.

By keeping the armature without the path or" the currentpassing through thc microphone, any choling or conflict between the magnetic flux of the receiving magnet and the magnetic Fini; introduced by the microphone current avoideda as of the magnet which, bvt'ore,

in the embodiment oi my invention de scribed the initial contact between the electrodes is enforced by the weight of the erniature-electrode structure and regulated by the directly alined andA accumulated initial and variable pull 'ol' the magnet. ln the modiiication shown in Figs. 3 and the fixed electrode is inverted and attached to the I bottom of the base p, the vibratory electrode 1e nl." being also inverted and connected to the armature by the elongated stud z' passing through the aperture in the lasse. ln this v construction the tivo electrodes are normally drawn toward each other by the initial pull can ce regu lated .acting against the force of grevity tending to 'separate them. Y I

ln. the form shown in Figsl 3 and 4l where o the magnet draws the electrodes 'into Contact :the stationary electrode forms an abutment imposing an approximate limit to the attractive pull of the magnet, so that the armature can normally loe brought into very close approximation to the magnet poles, thereby greatly increasing the intensity with which the line variations are imposed upon the microphone in the form of varying pressure between the contactV electrodes. ln this reo spect it is foreereble to the form shown in Figs. l and 2, where, it beingiinpossible in practice to regulate-the initial magnetism of the magnet with nicety and -exactness, any attempt to bring the armature too close to $5 the magnet poles may result in *lifting the 'armature into actuel Contact therewith. y My invention is not limited. to any particular microphonic lorni of Contact andv in Fig. 54 li' have yshownits principles applied "i9, 'to e microphone resistsnce employing apluralit v of carbon 'ooint electrodes r attached 'to a metallic alate Z and workin" coniiinction with' a lined electrode n and mass of interposed granular carbon "s, The lined i5 electrode n is providecl with a clouhle cylindrical partition Wall between which is freely movable a similar partition Wall attached' to the'vihratory plate Z, iviereby the loose carbon material is presenten from escapin a To illustrate a. further modification oflmy invention, in Figs. 7 and Sthere is shown en instrument similar to that shown in Figs. Eend 6,"the vibratory'electrode being in the form of a shallow cup-shaped structure carrying the loose carbon and compressing the'saine between the bottom of the cup yand downwardly directed. carbon points whichere att-scheel tothe xecl electrode.

lit will be noticed that, since the rigidly connected. armature and viliratory electrocle .move in a straight line, the movements of the armature in response to the vaiyins; 'cull oi the magnet to cause .no icc-lling" 5 movement 'wha ff oi the fiori-story desired, the initial magnetic pull Contact line.

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other, or, `for any other reason, the pull is eccentric, the electrode will still be held against rocking and continue to preserve a irin, even contact throughout its entire ei;-

Vtent instead ol tending to concentrate it et one point snel thereby decreasing the eiliciency of the apparatus, i 7ill be seen that in the construction shown in Figs. l to il, inclusive, the related electrode surfaces di verge `gradually and progressively from the En the described embodiment of iny invention desired simplicity obtained, this beine,- eiectefl hy the elimination oi' those mechanical enl'ects which are ordinarily present with attendant distortion.

' direction as the pull of the magnet and other c distortionless forces or factors, such, for ei;- ainpl'e, as those developed by the-compressibility oi' the carbon material, of the niicrophone, reliecl upon to control or position' the vibratory electrode. ln such a construction, as well :is those flisclosecl, gravity would act as a coordinating force without a distorteliegt upon the vibration of the electrons, 'and it is Within niy invention to eniploy coordinating 'forces other than gravity to so* .vith or against the icull of the receiving magnet, the vprincignil object of my invention being 'the suppression of distorting-E; factors in the construction and operation' of the repeater. y

iii-lille l have clescriliefl one forni'oi" my invetion, it is, of course, to he uiulerstood that the saine is not limited to the construction, form or respective arrangement of parte, either of the mechanical features, the

n'iicrophonic features, or the armature-electrefle structure, but that extensive modifications anni variations may be made therein without departing from `the spirit of the invention.

Claims:

l. ln :i telephonie apparatus, :z variable resistance medium comprising; an! annular electrode having an annular convex anal n an annular concave aceoi'greater curi/'in there is a greater coperatins; annuler electrons circuit, a magnet therein, a variable resistance medium comprising an annular electrode having a convex surface and a cooperating annular electrode having a concave surface ot greater curvature, the convert and concave surfaces of said electrode bearing one upon the other, an armature in magnetic relation to said magnet and connected with one of said electrodes for varying the pressure contact between them and hence the conductivity thereof.

3. ln a. telephone apparatus, a receiving circuit, a magnet therein, a variable resistance medium comprising a pair of annular electrodes, one having a convex surface bearing against. the surface ot the other electrode, and an armature in magnetic relation to said magnet and connected ith one of said electrodes for varying the pressure contact between them and hence the conductivity thereof.

a'. In a current varying instrument a fixed 'annular electrode, a movable annular electrode, one of said electrodes having a convex bearing surface, an armature to said movable electrode, a magnet adapted by its action upon said armature to maintain said electrodes in Contact, and means to vary the magnetic pull of said magnet.

5. In a current varying instrument a magnet, a movable electrode, a fixed annular electrode between the movable electrode and the magnet, and a magnet connection between the movable electrode and the magnet passing through the said annularelectrode.

G. ln a current varying instrument, the combination with a multi-Dolar magnet, of a ixed annular electrode, a movable annular electrode, and an armature connected to said movable' elect-rode, said electrodes having a diameter greater than the distance between the poles of said magnet.

7. In a 'telephone repeater having ya receiving circuit, a receiving magnet, a'tranemitting circuit containing a variable resistance transmitting medium having a movable electrode and a separate armature having a central connection to said electrode, said armature and connected electrode being' so far separated as to substantially remove the electrode fromvthe iniuence of the magnetic field constituting a connection. between the magnet and said medium having unrestricted vibratory movement due solely to the pullA of the magnet and the weight of the said connection, for the transmission ot currentl variations from the receiving circuit to the transmitting ci rcuit.

8. A telephone relay or repeater having an electro-magnet, a microphone and a magnetically suspended armature responsive to magnetic variations for actuating the microphone, all tbe lines of magnetic pull upon said armature lying ith'ia the limits ci miti/revelando Contact,

mg initially-ener to the pull of the magnet and the weight or the said connection for transmitting current variations from said receiving circuit to said transmitting circuit, all the lines of magnetic pull upon the armature lying within the limits of microplionic Contact.

l0. ln a telephone relay, in con bination, a microphone in series with its transmitting circuit and. comprising two solid electrodes shaped to give a linear contact surface symmetrically disposed about a center, the elecy trode surfaces diverging from the contacting line; a rigid support for one electrode; means to maint-ain unbroken contact be tween said electrodes; an armature centrally mounted on the Iother electrode; and a ceiving electro-magnet operatively related to said armature, said armature being subject wholly to the controlling influence oil gravity and said electro-magnet and the coil of said electro-magnet being operatively related to the receiving circuit.

ll. in a telephone relay in combination a microphone in series with a transmitting circuit and comprising two solid electrodes shaped to give a substantially circular linear contact in a plane therebetween and so that the related electrode surfaces diverge Y gradually and progressively from the con- 'ceived voice currents.

l2. ln a telephone relay, in combination, substantially vertically-positioned downwardly-pointing initially-encrgiied receiving magnet with a winding therefor adapted to be energized by received currents; a, microphone horizontally disposed below said magnet with a transmitting circuit and comprising two solid electrodes shaped to give' a sulistantially circular` linear contact with. diverging cont-art walls; a rigidmounting for` the upper electrode; andan armature` for-said magnet, conceiitrically and rigidly arranged on the lowerl electrode; whereby said electrodes are maintained in unbroken eontactby said magnet andsaid lower electrede is vibrated by the co-action of gravity and the received telephone currents.

131 ,in a telephone relay, in combination, a vertireilly-positioned downwardly-pointreceiving magnet Ulti with areceiving winding therefor; a horizontally 'positioned microphone therebelow, in series'with a transmitting circuit, and

comprising two solid electrodes shaped to give a linear contact surface symmetrically arranged about the central axis of attraction of said magnetra-rigid. support for the upper electrode, a block armature in the ieldof -said magnet, a stem connecting the armature centrally to the lower electrode and passing centrally through a free opening in the upper electrode; whereby said electrodes are maintained in unbroken con-` tact by said magnet and telephonically` vibrated by the received voice currents and gravity.

14. In a telephone relay, in combination,` with an initially magnetized receiving magnet and its armature, the latter operatively covering the pole or poles of said magnet, a microphone comprising two solid electrodes held in unbroken contact by the action of said magnet and formed to give anl electrode contact in linear form symmetrically and concentrically arranged' about the central axis of magnetic attraction on said armature; the magnet pole orpoles lying within the Jform inclosed by said contact line.

, 15. In a telephone relay, in combination, a vertically arranged, downwardly pointing electro-magnet with its coil in a receiving circuit, a horizontally positioned mic-rophone therebelow comprising solid electrodes ormedrto give an annular contact in horizontal plane between the converging` electrode surfaces; a fixed support for the upper electrode; an armature for said magnet and a` central rigid connection from said armature to the lower electrode structure; whereby said magnet and gravity action co-act to vibrate said movable electrode; the microphone annular contact diameter being in excess of thefrehited diameter of the magnet pole or poles and the associated armature; and atransmitting circuit in series with said microphone.

16. In combination, a microphone comprising two solid electrodes shaped to cause a linear Contact surface therebetween symmetrically disposed about a center, the elec trode surfaces gradually and progressively diverging from the contact line, and means to vary the pressure between said electrodes.

1T. In combination, a microphonecoim prising two solid electrodes shaped to cause a linear Contact surface therebetween sym-` metrically disposed in a plane and about a center, the' electrode surfaces diverging from the contact line at a progressively increasing angle, and means to vary the pressure between said electrodes at a right angle tothe Contact plane.

In testimony whereof, I have signed my name to this specification, vin the presence of two subscribing witnesses.

. CHARLES D. LANNING.

Witnesses THOMAS B. BOOTH, EDITH E. CHAPMAN. 

